The present invention relates to skin treatment apparatus of the type which provides water mist or vapor such as steam to the skin.
More particularly, the present invention relates to a facial sauna product which provides a cost-effective, easy-to-manufacture vaporizer using a non-electric temperature control system. The product will include overfill protection whether the unit is operating or not operating.
In the past, vaporizers and the like employed a variety of temperature control schemes. Examples include the mechanically controlling of the amount of input air, as disclosed in U.S. Pat. No. 3,511,236, or electrically controlling the fan/motor assembly as disclosed in U.S. Pat. No. 3,749,092 to provide a temperature range for steam to be applied to an area of the skin such as the face. Units which deliver steam and permit the user to fill the steam chamber when the steam chamber is pressurized and/or includes steam may be dangerous to the user. Thus, configurations which may allow the consumer to access the steam chamber, such as for refill while the unit is activated should be avoided. Further, steam units should be designed in a manner which provides overfill protection both when the unit is activated and when the unit is not activated. This is especially important when a compact design necessitates the use of a relatively small boiler which must maintain sufficient free head space to operate efficiently.
Briefly stated and according to an embodiment of this invention, the problems with the prior art devices have been overcome by the practice of this invention which include a steam chamber or boiler having in its associated fill means a one-way valve, such as an umbrella valve, which permits water to enter the boiler only when there is not sufficient steam or pressure in the boiler. The associated valve not only prevents the introduction of water into the boiler when the blower or fan is activated causing a pressure increase in the boiler but also prevents steam from escaping from the fill well due to the valve's one-way action. Overfill protection for the boiler, when the unit is "off," is provided by a drain communicating between the exterior of the housing and the interior of the boiler. The drain tube will be pinched off, or the like, when the unit is activated in an automatic manner such as by being mechanically linked to the start or "on" position of the associated control knob which also controls the effective area of the input vents to provide temperature control.